Edwin t



Patented 001;.31, 1882L (No Model.)

n E. T, GRBENFIELD.

SAFETY 0R CUPON SWTGH,

WEZ/1 afge@ Unirse stares PATENT erica y EDWIN T. GREENFIELD, OF-NEW YORK, N. Y., ASSIGNOR OF ONE-HALF TO SIGMUND BERGMANN, OF SAME PLACE.

SAFETY OR CUT-OFF SWITCH.

SPECIFICATION forming part of Letters Patent No. 266,808, dated October 31, 1882.

Application filed June 8, 1882.

To alt whom it may concern:

Be it known that I, EDWIN T. GREENFIELD, ot' New York, in the county and State of New York, have invented a certain new and useful Improvement in Salety or Out-Oft Switches, of which the following` is a speciiication.

The object of my improvement is to provide a simple and eti'cacious safety-switch or cutout for use with electriclamps.

To this end the improvement consistsin the combination, with the line-wire ot' a circuit leading to an electric lamp or other article, ot' a section of wires, an insulating material securing them in position, and adapted to melt when the wires become heated to a dangerous extent, so as to release the wires, a spring tending to move one end ot' the pliable wire or wires away and break the circuit, and a receptacle containing the said pliable wire or wires and insulating material. Preferably I form the section of wires and their insulating material into a plug or short rod.

In the accoml'ianying drawings, Figure l is a transverse section of a safetyswitch or cutout embodying my improvement, and Fig. 2 is an enlarged sectional view ot' a plug comprised in the same.

Similar letters of reference designate corresponding parts in both figures.

A designates a block ot' wood or other suita` ble material, which maybe ofcylindrical shape. As shown, it has an annular groove, a, in its upper tace, and a central cavity, I). To the interior of the cavity b is secured a screwthreaded metal ring, B, and to the bottom ot' the cavity is secured a metal plate, O. The plate O is insulated from the ring B by a piece ot insulating material, d, or by the material ot' which the bloek .A is made. In the groove a are two metal plates, D D. One end of the line-wire E, with which this safety-switch or cut-oli' is used, is connected to the plate D, and the other end thereofis connected to the plate D. A wire, F, is afxed by solder or otherwise to the plate D, and likewise to the ring B. A wire, G, is soldered or otherwise connected to the plates C and D.

H designates a piece of wood or other suitable material, having applied to its exterior a screw-threaded metal ring, I, which is adapted to screw into the ring B. The piece H is hol- (No model.)

low, and has affixed to its lower end a metal plate, J. This metal plate J makes contact with the metal plate O when the piece H is inserted in the ring B. In the piece H is a plug, u P, consisting ot two metal heads, c c', a number ot' softpliable metal wires,f, connected to the heads, and an insulating material, g, incasing these wires and sustainingthem straightened out and in parallel positions. This plug tits into the cavity or interior of the piece H, and one ot its heads, e, rests on the plate J. The other head, c', of the plug bears against a plate, K, which is ai'iixed to the outer end ot' the cavity in the said piece H. In lieu of the plate K, a screw inserted in the piece H may be employed. A wire, M, extends from the plate K, or the device which is employed in lieu thereof, to the screw-threaded ring I.

L designates a retractible spring arranged in the cavity ot' the piece H and surrounding the plug P. The lower end of this spring is titted into the head c ot' the plug, or in any other suitable manner is made to sustain the plug, and the upper end of the spring is secured to the interior ol' the piece H. This spring therefore exerts a constant tendency to force the head c ot' the plug I up toward the head c. So long as the insulating material of the plug is intact it preserves the relations of 8o the heads of the plug, but as soon as the wires of the plug become heated to a certain degree the insulating material melts and no longer sustains the heads in their normal relations, and the wires of the plug are insui'iicientlystiit' 85 for thispurpose. The spring therefore forces up the head e toward the head c, and by rcmoving the head c from the plate Jbrealts the circuit. The wires ot' a circuit in which the plug P is arranged can never become heated 9o to a degree greater than that which will melt the insulating material ot' the plug. This insulating material may consist ot' sealing-wax or other suitable substance.

The block A and piece H obviously form a receptacle inclosing the wires, insulating material, and spring.

What I claim as my invention, and desire to secure by Letters Patent, is-

I. The combination, with the line-wire ot' a ico circuit leading to an electric lamp or other article, of a section of pliable wire or wires, an

ICL.

insulating material sustaining the same eX- tended and adapted to melt when the said pliable'wire or wires become heated to an undesirable extent, so as to release said pliable Wire or Wires, a spring tending` to nieve said pliable wire er Wires away and break tbe eireuit, and a receptacle containing tbe said pliable wire or wires and insulating materia-l, substantially as specied.

2. The combination, with tbe line-wire ot'a circuit, of a plug fni'niing a part ot'tlie circuit, and consisting et metallic heads Connecting a pliable wire o1' wires, and insulating material ineasing tbe pliable wire o1' Wiresand adapted to nielt at any desired heat, a spring tending to move one end of the pliable wire or wires ecegses' lVitnesses:

T. J. KEANE, JAMES R. BOWEN. 

